How accurate is 'mapmyride'?

GT_TDI_150

Guys,

I mapped a cycle today, which 13.78miles(22.2km) in my car it measures @22.8km and the speedo fitted to the bike has it @ 22.5km.

Just wondering what peoples experience of this is?

Ricky91t

Well it maps based on GPS, The signal can vary, I think it also maps it on to google maps roads where possible which could be slightly out.

To be honest It seems accurate enough for me anyway.

niceonetom

Traditional cycle computers rely on knowing the circumference of your wheel very accurately - even a small error there is multiplied by the number of revolutions the wheel makes. I guess car speedos work the same. On that basis I'd be inclined to go with RWGPS.

ROK ON

niceonetom wrote: »

Traditional cycle computers rely on knowing the circumference of your wheel very accurately - even a small error there is multiplied by the number of revolutions the wheel makes. I guess car speedos work the same. On that basis I'd be inclined to go with RWGPS.

RWGPS is by far a better interface than MMR. However I find that RWGPS completely overestimates the amount of climbing in a ride and often severely underestimates the gradient of climbs. MMR while its a pain in the jacksie is more accurate in capturing the true nature of the climbs that I have done at any rate.

niceonetom

Elevation is totally different issue to distance - it relies on using a sample rate and algorithm to calculate a figure and you could make a legitimate argument that almost any number is 'accurate' for elevation gained or lost over a route. Indeed, you could argue (though I wouldn't) that the elevation gain of any route approaches infinity given the nearly fractal lumpiness of Irish roads.

cantalach

Both MMR and RWGPS rely on Google Maps for route plotting and this represents roads as a series of straight line segments. For any route (other than one along a dead straight road) this results in an underestimation of the total distance. Worse still, on minor roads in remote areas I've noticed that this straight line segmentation is very coarse-grained and often far removed from the reality. As well as causing underestimationg of distance, another unfortunate consequence of this is that if you plot a route on RWGPS and then transfer it to your Garmin to follow the route, the device will frequently report that you are gone off course.

Inquitus

In my experience mapmyride isn't great, but its not terrible either.

iregk

Well in fairness would you really worry about a .5 difference or that between MMR and your bike? What you have to realise as well is that MMR essentially goes straight line on the roads. While you are out cycling your front wheel may be veering at times thus adding on distance. I saw many people slalom up Sleave Mann and SE during the W200. That would add additional distance, but not a lot.

As long as you're not a few km's out then I wouldn't be overly concerned. While mapping is a pain in the hole on it once you're done I find the gradient information a lot more accurate than other sites.

SachaJ

Car speedos are known to be out by up to 7%. So if you were doing 100kmph according to the car, your actual is probably closer to 93kmph.